Some JavaScript extensions

common.js

if (!String.prototype.ucFirst) {
    (function() {
        String.prototype.ucFirst = function() {
            var str = this;
            if (str.length) {
                str = str.charAt(0).toUpperCase() + str.slice(1);
            }
            return str;
        };
    })();
}

if (!String.prototype.lcFirst) {
    (function() {
        String.prototype.lcFirst = function() {
            var str = this;
            if (str.length) {
                str = str.charAt(0).toLowerCase() + str.slice(1);
            }
            return str;
        };
    })();
}

if (!String.prototype.ucWords) {
    (function() {
        String.prototype.ucWords = function() {
            var str = this.toLowerCase();
            return str.replace(/(^([a-zA-Z\p{M}]))|([ -][a-zA-Z\p{M}])/g,
                function(s){
                    return s.toUpperCase();
                });
        };
    })();
}

if (!String.prototype.format) {
    String.prototype.format = function() {
        var args = arguments;
        return this.replace(/{(\d+)}/g, function(match, number) {
            return typeof args[number] != 'undefined'
                ? args[number]
                : match
                ;
        });
    };
}

if (!String.prototype.superTrim) {
    (function() {
        String.prototype.superTrim = function(characters) {
            var str = this;
            var charArray = characters.split('');
            var result  = '';

            for (var i = 0; i < charArray.length; i++)
                result += '\\' + charArray[i];

            return str.replace(new RegExp('^[' + result + ']+|['+ result +']+$', 'g'), '');
        };
    })();
}

if (!String.prototype.isNumeric) {
    (function() {
        String.prototype.isNumeric = function() {
            return !isNaN(parseInt(this, 10));
        };
    })();
}